Such a motor vehicle is known from U.S. Pat. No. 8,280,623 B2. The vehicle can assume control if an obstacle suddenly appears or if the driver is overtaxed by a driving situation or physically incapable of controlling the vehicle. An adverse effect on the driver can be detected by virtue of the fact that the vehicle has a left a predetermined path and also the steering wheel or pedals have not been activated for a relatively long time. The vehicle can also bring about an emergency stop, wherein the vehicle is brought to a standstill under autonomous control. This obviously takes place rather slowly and not with the maximum braking force as in the case of a genuine emergency braking operation.
U.S. Pat. No. 8,352,110 B2 discloses a motor vehicle which is capable of autonomous driving and which detects adverse effects on the driver while he is driving the vehicle, on the basis of signals of contact sensors on the steering wheel, and if appropriate assumes control of the steering wheel.
Contemporary motor vehicles are frequently equipped with an emergency braking assistant which detects obstacles and which, if the distance from an obstacle becomes too small without the driver correspondingly reacting, triggers full braking in order to avoid a collision with the obstacle, or at least to reduce the severity of the impact. As a result, an emergency braking assistant differs from a braking assistant which merely constitutes a brake booster which is part of the area of responsibility of the vehicle driver, and also from an emergency stop device for terminating travel in the event of an adverse effect on the driver which unexpectedly occurs.
An emergency braking assistant can be implemented using a conventional vacuum brake system which uses a pump in the brake module, said pump being used for a vehicle movement dynamics controller (electronic stability control; ESC) or anti-lock brake system (ABS), in order to actuate the brakes independently of activation of the brake pedal by the driver.
An emergency braking assistant builds up the braking force or the brake pressure along a preset characteristic curve as a function of time which passes from a partial braking operation to a full braking operation. This characteristic curve is often a ramp function which rises with an approximately constant gradient from zero to a maximum value and maintains said maximum value for a certain time. The characteristic curve for the braking force or brake pressure for an emergency braking operation is preset in such a way that it matches a driver who is normally in control of the vehicle.
The invention is based on the object of being able to provide a motor vehicle which is capable of autonomous driving with an emergency braking assistant.